[Objective] The effects of application researches of humic acid in soil improvement and pollution remediation were summarized in order to provide a significant reference for application research and product development of humic acid. [Methods] Based on the long-term researches on characteristics and practical application of humic acid resources, and referring to a large number of academic literatures on humic acid research, the principle, technology and application of humic acid in soil improvement and remediation of soil pollution were comprehensively analyzed. [Results] Humic acid can improve soil aggregate structure, improve fertilizer utilization efficiency, maintain soil acid-alkali balance, and promote soil biological activity. Humic acid plays an important role in mitigating the degradation of soil, improving saline-alkali land, reclaiming abandoned land, and remediating heavy metal and organic pollution of soil. At present, there are some problems regarding the application researches in soil improvement and pollution remediation. ① The sources and classification of humic acid are unclear, and basic researches are insufficient. ② Research and development of new humic acid materials and technologies are slow, and the overall technology of the industry needs to be improved. ③ The construction of technical specifications and standards in humic acid does not match the application and development of humic acid, thereby limiting the speed of promotion. [Conclusion] Future research emphasis should be placed on the following areas: ① Basic research on classification, component separation, and interaction between coal-based and biological humic acid resources. ② Applied basic research on humic acid in soil improvement and pollution remediation. ③ Researches on detection methods and formulation of product quality standards of humic acid. ④ Applied researches and development on new humic acid products and construction of demonstration parks.